/*
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 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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 */

/*      Copyright (c) 1988 AT&T */
/*        All Rights Reserved   */

/**
 * Implements the UNIX crypt(3) function, based on a direct port of the
 * libc crypt function.
 *
 * <p>
 * From the crypt man page:
 * <p>
 * crypt() is the password encryption routine, based on the NBS
 * Data  Encryption  Standard,  with variations intended (among
 * other things) to frustrate use of  hardware  implementations
 * of the DES for key search.
 * <p>
 * The first argument to crypt() is  normally  a  user's  typed
 * password.   The  second  is a 2-character string chosen from
 * the set [a-zA-Z0-9./].  the  salt string is used to perturb
 * the DES algorithm in one
 * of 4096 different ways, after which the password is used  as
 * the  key  to  encrypt  repeatedly  a  constant  string.  The
 * returned value points to the encrypted password, in the same
 * alphabet as the salt.  The first two characters are the salt
 * itself.
 *
 * @author Roland Schemers
 */

package com.sun.security.auth.module;

class Crypt {

    /* EXPORT DELETE START */

    private static final byte[] IP = { 58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8, 57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3, 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7, };

    private static final byte[] FP = { 40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23, 63, 31, 38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29, 36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27, 34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49, 17, 57, 25, };

    private static final byte[] PC1_C = { 57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43, 35, 27, 19, 11, 3, 60, 52, 44, 36, };

    private static final byte[] PC1_D = { 63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4, };

    private static final byte[] shifts = { 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1, };

    private static final byte[] PC2_C = { 14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10, 23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2, };

    private static final byte[] PC2_D = { 41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48, 44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32, };

    private byte[] C = new byte[28];
    private byte[] D = new byte[28];

    private byte[] KS;

    private byte[] E = new byte[48];

    private static final byte[] e2 = { 32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17, 16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1, };

    private void setkey(byte[] key) {
        int i, j, k;
        byte t;

        if (KS == null) {
            KS = new byte[16 * 48];
        }

        for (i = 0; i < 28; i++) {
            C[i] = key[PC1_C[i] - 1];
            D[i] = key[PC1_D[i] - 1];
        }
        for (i = 0; i < 16; i++) {
            for (k = 0; k < shifts[i]; k++) {
                t = C[0];
                for (j = 0; j < 28 - 1; j++)
                    C[j] = C[j + 1];
                C[27] = t;
                t = D[0];
                for (j = 0; j < 28 - 1; j++)
                    D[j] = D[j + 1];
                D[27] = t;
            }
            for (j = 0; j < 24; j++) {
                int index = i * 48;

                KS[index + j] = C[PC2_C[j] - 1];
                KS[index + j + 24] = D[PC2_D[j] - 28 - 1];
            }
        }
        for (i = 0; i < 48; i++)
            E[i] = e2[i];
    }

    private static final byte[][] S = { { 14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7, 0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8, 4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0, 15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13 },

            { 15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10, 3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5, 0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15, 13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9 },

            { 10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8, 13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1, 13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7, 1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12 },

            { 7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15, 13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9, 10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4, 3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14 },

            { 2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9, 14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6, 4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14, 11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3 },

            { 12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11, 10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8, 9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6, 4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13 },

            { 4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1, 13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6, 1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2, 6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12 },

            { 13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7, 1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2, 7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8, 2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11 }, };

    private static final byte[] P = { 16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10, 2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25, };

    private byte[] L = new byte[64];
    private byte[] tempL = new byte[32];
    private byte[] f = new byte[32];
    private byte[] preS = new byte[48];

    private void encrypt(byte[] block, int fake) {
        int i;
        int t, j, k;
        int R = 32; // &L[32]

        if (KS == null) {
            KS = new byte[16 * 48];
        }

        for (j = 0; j < 64; j++) {
            L[j] = block[IP[j] - 1];
        }
        for (i = 0; i < 16; i++) {
            int index = i * 48;

            for (j = 0; j < 32; j++) {
                tempL[j] = L[R + j];
            }
            for (j = 0; j < 48; j++) {
                preS[j] = (byte) (L[R + E[j] - 1] ^ KS[index + j]);
            }
            for (j = 0; j < 8; j++) {
                t = 6 * j;
                k = S[j][(preS[t + 0] << 5) + (preS[t + 1] << 3) + (preS[t + 2] << 2) + (preS[t + 3] << 1) + (preS[t + 4] << 0) + (preS[t + 5] << 4)];
                t = 4 * j;
                f[t + 0] = (byte) ((k >> 3) & 01);
                f[t + 1] = (byte) ((k >> 2) & 01);
                f[t + 2] = (byte) ((k >> 1) & 01);
                f[t + 3] = (byte) ((k >> 0) & 01);
            }
            for (j = 0; j < 32; j++) {
                L[R + j] = (byte) (L[j] ^ f[P[j] - 1]);
            }
            for (j = 0; j < 32; j++) {
                L[j] = tempL[j];
            }
        }
        for (j = 0; j < 32; j++) {
            t = L[j];
            L[j] = L[R + j];
            L[R + j] = (byte) t;
        }
        for (j = 0; j < 64; j++) {
            block[j] = L[FP[j] - 1];
        }
    }

    /* EXPORT DELETE END */

    /**
     * Creates a new Crypt object for use with the crypt method.
     *
     */

    public Crypt() {
        // does nothing at this time
        super();
    }

    /**
     * Implements the libc crypt(3) function.
     *
     * @param pw the password to "encrypt".
     *
     * @param salt the salt to use.
     *
     * @return A new byte[13] array that contains the encrypted
     * password. The first two characters are the salt.
     *
     */

    public synchronized byte[] crypt(byte[] pw, byte[] salt) {
        int c, i, j, pwi;
        byte temp;
        byte[] block = new byte[66];
        byte[] iobuf = new byte[13];

        /* EXPORT DELETE START */

        pwi = 0;

        for (i = 0; pwi < pw.length && i < 64; pwi++) {
            c = pw[pwi];
            for (j = 0; j < 7; j++, i++) {
                block[i] = (byte) ((c >> (6 - j)) & 01);
            }
            i++;
        }

        setkey(block);

        for (i = 0; i < 66; i++) {
            block[i] = 0;
        }

        for (i = 0; i < 2; i++) {
            c = salt[i];
            iobuf[i] = (byte) c;
            if (c > 'Z')
                c -= 6;
            if (c > '9')
                c -= 7;
            c -= '.';
            for (j = 0; j < 6; j++) {
                if (((c >> j) & 01) != 0) {
                    temp = E[6 * i + j];
                    E[6 * i + j] = E[6 * i + j + 24];
                    E[6 * i + j + 24] = temp;
                }
            }
        }

        for (i = 0; i < 25; i++) {
            encrypt(block, 0);
        }

        for (i = 0; i < 11; i++) {
            c = 0;
            for (j = 0; j < 6; j++) {
                c <<= 1;
                c |= block[6 * i + j];
            }
            c += '.';
            if (c > '9') {
                c += 7;
            }
            if (c > 'Z') {
                c += 6;
            }
            iobuf[i + 2] = (byte) c;
        }
        //iobuf[i+2] = 0;
        if (iobuf[1] == 0) {
            iobuf[1] = iobuf[0];
        }
        /* EXPORT DELETE END */
        return (iobuf);
    }

    /**
     * program to test the crypt routine.
     *
     * The first parameter is the cleartext password, the second is
     * the salt to use. The salt should be two characters from the
     * set [a-zA-Z0-9./]. Outputs the crypt result.
     *
     * @param arg command line arguments.
     *
     */

    public static void main(String arg[]) {

        if (arg.length != 2) {
            System.err.println("usage: Crypt password salt");
            System.exit(1);
        }

        Crypt c = new Crypt();
        try {
            byte result[] = c.crypt(arg[0].getBytes("ISO-8859-1"), arg[1].getBytes("ISO-8859-1"));
            for (int i = 0; i < result.length; i++) {
                System.out.println(" " + i + " " + (char) result[i]);
            }
        } catch (java.io.UnsupportedEncodingException uee) {
            // cannot happen
        }
    }
}
